RewindexCVEsAmazon Web Services
CVE-2026-4270: AWS API MCP File Access Restriction Bypass
Medium · CVSS 5.5 (CVSS 3.1)EPSS 0.13%, 3th percentilePublished Updated Assigner: AMZN
Description
Improper Protection of Alternate Path exists in the no-access and workdir feature of the AWS API MCP Server versions >= 0.2.14 and < 1.3.9 on all platforms may allow the bypass of intended file access restriction and expose arbitrary local file contents in the MCP client application context. To remediate this issue, users should upgrade to version 1.3.9.
Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N · CWE-424
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
AWS: AWS API MCP Server
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- aws.amazon.com/security/security-bulletins/2026-007-AWS/ (opens in new tab)
- pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/ (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)